Ran my 2011 Pruis out of gas today

Happens to lots of people (including myself) and it is usually the same reason: trying to push the tank to the next 100 mark even though you know you shouldn't have.

When the Prius says you should fill up, fill up.

 

Or sooner

 

BTW doing the math you got 49.5mpg.

Not worth the potential damage. If your battery had been low you would've been sitting in a Toyota lobby.

 

I would say that there is a sort of "peace of mind" factor here that you can just go off the battery should you run out of gas. Someone said it couldn't be done with the Gen3 only the Gen2.

I would never try to run my tank to the last drop but I'm curious as to what sort of potential damage could come in play if you ran without gas? Damaged fuel pump? Extreme wear on the battery?

 

Toyota programs the SOC limits to 40% and 80%. So when your display reads full (100%) the battery is actually 80% charged. When your display reads 1 bar (12.5%) the battery is actually 40% charged. There is a very important reason for this: It is the maximum safe/reliable battery swing range that allows the battery to have minimal degradation over hundreds of thousands of miles which is no easy feat.

When you run out of gas and engage limp-along mode, the safety control limits are disengaged for the lower bound. Not sure anyone has attempted to verify they are disabled for the higher bound as you would have to run out of gas on a mountain then turn around and regen all the way down. So when the safety is disengaged, you can run the car until it just doesn't move anymore. Usually that is well below the 40% minimum "safe" threshold. The more deeply you discharge it, and the more often you do it, the less life the battery will have. You did not go below 15% to 20% because the car started when you were done.

When the Prius is off, the HV battery is disconnected from the system completely by 2 large relays. When you go ready, the 12v battery flips the 2 relays (the first to current limit the initial connection), which engages the HV pack. With a low pack, it will not wait the normal 7 seconds to start the engine it will do so immediately. Now the Prius has no starter, it uses an MG to spin the engine then inject fuel and keep it moving. If the HV battery is too low it cannot spin MG to start the ICE. Now you have a chicken and the egg problem. The ICE is needed to recharge the HV battery pack, and the HV pack doesn't have enough charge to spin the ICE... So now you are dead. You must be towed to a Toyota dealership so they can fly in one of the tens of units around the world that allows for charging of the HV pack from a wall socket. The procedure is actually comical as they must put a thick band of caution tape around your car and the high voltage dc charger while they fool the computer into thinking it is READY so it accepts the wall charge up to the 40% limit. Yeah, this will cost you a pretty penny.

Since you have a GenIII you don't have to worry about the bladder, but in GenII running out may crease the bladder in such a way that it is very difficult to inflate it back fully. It will happen eventually, but it will probably take a while.

 

Here is the charger:

 

what consumes one to run their tank empty ??? not good practice ! change your ways don't run your fuel pump when your tank is low, often. the pump runs hotter at that point you will make it croak!!!! and then you will also run the risk of draining the traction batt and its over for you bud you will have to go ta the dealer for a special charge of it !!!! be careful hahahaaa

 

2k1Toaster, OMG!! What a pain in the A$$. Somebody hack my Prius please. (Need SCib batteries soon!).

 

Just lucky sometimes? My first car in the 70's changed the oil and filter. Test drove about 2 blocks and turned around because engine was making a terrible racket. Pulled into my garage and yep all 4 quarts of oil still in the cans sitting on the floor. Kept the car for 3 more years never burned a drop of oil between changes. Lucky i was now i don't tempt fate, never run gas low and double triple check all oil changes lol.

 

It didn't happened with me because I used to get my tank full.

 

There is thread on PC where Bob Wilson ran his Gen III out of gas a few times to see what would happen.
http://priuschat.com/forums/gen-iii-2010-prius-main-forum/64211-warning-running-out-gas-gen-iii.html
He drove it until it stopped and the sky didn't fall. The car quit moving completely while there was still adequate charge in the 12 volt and traction batteries to restart the car when he added gasoline.

I believe the scenario that you described is true for the Gen II. I suspect it was fixed on the III because of the problems you described.

As an aside, if all the tongue clucking by old ladies of both genders in Bobs thread could be turned into useful energy, you could run a car on it.

Note: At the start of that thread Bob said the car wouldn't run on battery power adter the engine quit. Many posts later in the thread he discovered it will run on battery power after the engine runs out of gas
http://priuschat.com/forums/gen-iii...ng-running-out-gas-gen-iii-19.html#post895056

 

Why risk it?

I'm sure you could do a few miles without coolant (In fact I know you can) but why take the chance when the car gives you nearly 100 miles of warning?

 

Why not get gas when the tank is 1/2 full? You never know when you might find yourself in a traffic jam!

 

Because it's twice as many trips to the gas station! Bob Wilson's tests showed about 2.1 gallons left in the tank when the last bar starts flashing. That's 100 miles or so, which is PLENTY of time to fill up.

 

I would find it embarrassing to run out of gas.

I have run it so that no bars show, but I don't usually do that.

 

You really shouldn't run your tank that low because there is a fuel pump in the tank. If gas is sloshing around and the pump is sucking air, that is bad for it.

Like said before, gas up when the car's blinking pip tells you to do so.

 

If you run it out of gas, your fuel pump will eventually give out. It needs gas to cool it down. Sounds weird, I know, but fuel pumps are liquid cooled and gas = liquid.

 

You mean the last blinking one will eventually go away?